Roller burnishing tool

ABSTRACT

To provide a roller-burnishing tool, the usage by installing in a small machining center, small NC lathe and so forth is offered. The frame  2  for rolling compaction processing is coaxially connecting with the shank portion  3  which is performing a rotary drive by mounting in a driving machine, and the mandrel  6  is supported by this frame  2  with universal function for rotation. A tip end  6   a  of the mandrel  6  and the multiple roller  5,5  are formed into a taper shaped style for being supported by a rotation from a radial direction. The mandrel  6  and the compressing coil spring  13,  which is impetuous from the shank portion  3  side to the frame  2  side are provided in the shank portion  3  as well as the adjustable ring  8 , which is to adjust a tool diameter by moving the position of an axial direction to the frame  2  of the mandrel  6.

BACKGROUND OF THE INVENTION

[0001] 1. Field of Invention

[0002] The present invention relates to a roller-burnishing tool to process an inner surface of a work hole, and more particularly to a roller-burnishing tool to finish inner holes of small parts in the wide range of fields such as automobile, home electronic appliance, semiconductor and so forth by a rolling compaction of multiple rollers.

[0003] 2. Prior Art

[0004] As this kind of a roller-burnishing tool, for example, such as the like indicated in Japanese Utility Model Publication No.64-275 is common.

[0005]FIG. 1A and FIG. 1B illustrates this kind of roller-burnishing tool 111. The multiple rollers 113,113 to carry out a rolling compaction processing of an inner work hole W1 of a work W is engaged in a tip of an outer circumference of the cylindrical frame 112 with universal function for rising and setting and rotating, and the mandrel 114 formed as transmitting a rotary driving force is imbedded in said frame 112 with rotary supporting of these roller 113 from the center axis of the frame 112. These structure imparts a rotary driving to this mandrel 114 through the shank 115 by a driving machine such as a machine tool, a rotary drill and so forth.

[0006] In said roller burnishing tool 111, when adjusting the diameter (hereinafter called as a tool diameter) of enveloping circle of multiple roller 113,113 for the internal diameter of the work hole W1, move the mandrel 114 supported by screwing in the screw hole 117 processed on the rear of the housing parts 116 connected with an outer diameter of said frame 112 forward and backward, adjust the degree of rising and setting of each rollers 113 for the outer circumference of frame 112 by changing the position of contacting a tip of the taper shaped mandrel 114 with each roller 113.

[0007] In this way, however, the structure of positioning the mechanism outside frame 112 to adjust a tool diameter is not applicable for effective downsizing and lightening since the compression and downsizing of tool length has automatically limitation.

[0008] Accordingly, in this kind of roller-burnishing tool, the protrudent length of a tip side of the frame 112 and the housing part 116 are automatically longer than the shank 115, so the usage for installing in a miniature type of machining center and NC lathe and so forth is infeasible.

[0009] In addition, the method of driving roller 113, 113, being transmitted through the rotary driving of the mandrel 114 can not be obtain a floating function even though setting a clearance in radial direction between the mandrel 114 and the frame 112.

[0010] Hence, this can not be sufficiently applicable for an eccentricity of a work hole. In addition, the improvement of an efficient rapid rotation is difficult since the tool rigidity is low due to the structure of imparting a rotary drive to a detailed mandrel 114 positioning along an axis of the frame 112.

[0011] Moreover, when tweaking a tool diameter, the position of the roller 113,113 is also moved due to the structure of adjusting a tool diameter by moving the frame 112 in an axial direction when adjusting a tool diameter. Whenever this, a readjustment of stroke in the driving machine is indispensable which has been a shortcoming. The purpose of the present invention is subject to solve this shortcoming.

SUMMRY OF THE INVENTION

[0012] The first invention of this document is to provide the roller-burnishing tool, which comprised:

[0013] A cylindrical frame for a rolling compaction processing is coaxially connected with a cylindrical shank portion, which is performing a rotary drive by mounting in a driving machine. The multiple rollers for rolling compaction processing are formed in a radial direction along this frame with universal function for rising and setting, and the grooves to engage said rollers are formed in circular direction at regular intervals along this frame with universal function for rotation. Then with engaging said rollers in said grooves, Said multiple rollers on the tip and the taper shaped mandrel to be supported by rotation from inside radial direction are fit into said shank portion and frame with universal function for rotation. And thereafter, the adjustable method is provided to adjust a tool diameter by moving a position of an axial direction for said frame of said mandrel as well as the elastic method in said shank portion to stimulate said mandrel from the shank portion side to the frame side.

[0014] The second invention of this document is to provide the roller-burnishing tool in said first invention, which comprised:

[0015] When reversing the rotation of said frame to a processing direction, the feed angle to allow a tip of said mandrel to move from said frame side to said shank side is provided in both said grooves of said frame and the rotation axis of said rollers engaged in a grooves.

[0016] Moreover, the third invention of this document is to provide the roller-burnishing tool in said first invention and said second invention, which comprised:

[0017] The clearance is provided in between an outer circumference of said mandrel and an inner surface of said frame to allow this mandrel to float.

[0018] In the first invention, when inserting said frame into the work holes with normal rotation drive, each roller contacts with a tip taper shaped mandrel and begin to revolve by relative friction force generated in between.

[0019] In this time, each roller dependently rotates in accordance with the rotation of frame since the mandrel is free from a rotary direction for being supported by freely rotatable condition. The rolling compaction force of a roller for an inner work hole depends upon the gap between a tool diameter and a work hole.

[0020] Owning to the structure of driving a frame, it makes possible for rollers to perform a rapid feeding processing by the principle of a planetary motion compared with the structure of driving a conventional mandrel.

[0021] Of course owning to the structure of coaxially positioning the mandrel in the center axis of the frame improves a rotational accuracy which leads capable for a rapid rotation, and moreover, coaxially connecting the frame with shank portion of rotary drive improves a rotational accuracy which allows rollers to perform a rapid rotation with high accuracy.

[0022] Hence, whole efficiency is significantly improved compared with a conventional one.

[0023] In the second invention of this document, when reversing the rotation of said frame, a retreat force is generated in the mandrel by the agency of a feed angel θ, the tool diameter is shrunken when this retreated force exceeds the impetus force of said elastic method. Accordingly, only reversing the rotation of the frame makes possible to easily withdraw frame from a work hole.

[0024] And the feed angle is provided into each groove for engaging rollers. Imparting normal rotary motion to the frame keeps a tool diameter initial set value.

[0025] When retreating, reversing the rotation of the frame causes the taper shaped mandrel to move backward to the shank portion and each roller dive into inside radial direction. Hence, tool diameter is shrunken, quick withdrawing becomes practical.

[0026] When the frame is withdrawn from inside of a work, the tool diameter returns to an initial state by accumulated impetus of an elastic method imbedded in the shank portion.

[0027] Moreover, In the third invention, since the mandrel is floating in a radial direction of the clearance between an inter diameter of the frame and the mandrel, processing accuracy is sustainable even under the condition of establishing a tool diameter on the position slightly slipped from the center of the work hole.

BRIEF EXPLANATION OF THE DRAWING

[0028]FIG. 1. Illustrates the conventional example, FIG. 1A illustrates a half-sectional view of the roller-burnishing tool. FIG. 1B illustrates a tip of the mandrel, and the X-X sectional view of FIG. 1A indicates a contact condition of the roller with the frame.

[0029]FIG. 2. Illustrates the formation of implementing the roller-burnishing tool regarding to this invention. FIG. 2A is a half-sectional view of the roller-burnishing tool, FIG. 2B is a perspective view to indicate the structure of an adjustable screw and an adjustable ring.

[0030]FIG. 3. The explanation diagram to indicate the situation of the normal direction of the rotation and forward moving of the roller-burnishing regarding to work holes to illustrate the formation of implementing of the roller burnishing tool regarding to this invention.

[0031]FIG. 4. The explanation drawing to indicate the situation of withdrawing a roller-burnishing tool from work holes to illustrate the formation of implementing of the roller burnishing tool regarding to this invention.

[0032]FIG. 5. The explanation drawing to indicate the situation of absorbing an eccentricity of the roller banishing tool for work holes to illustrate the formation of implementing of the roller burnishing tool regarding to this invention.

DETAILED EXPLANATION OF THE PREFERED EMBODIMENTS OF THE INVENTION

[0033] Following is the explanation of the implemented formation as reference to FIG. 2 to FIG. 5. FIG. 2 illustrates the roller-burnishing tool regarding to implemented formation. Like Illustration, the main body of the roller banishing tool 1 consists of the cylindrical frame 2 and the shank part 3, the frame 2 for a rolling compaction processing is coaxialy linked with a tip of the cylindrical shank part 3 to be driven by installing in the driving machine (not shown) of a machining hole, etc. The grooves 4,4 for engaging multiple rollers are provided in a circumferential direction at regular intervals along the tip of outer circumference 2 a of said frame 2, the rollers 5 for rolling compaction machining are engaged with each groove 4,4 for engaging a roller in a radial direction with universal function for setting and rolling and rotation. Said grooves 4,4 for engaging roller are provided with a lean of predetermined angle θ against the axial line of said frame 2, said roller 5,5 engaged with the grooves4,4 for engaging roller from inside axial direction of the frame 2 are supported by the rotation of a tip 6 a of the mandrel 6 connected with the frame 2 and the shank portion 3. Said mandrel 6 is inserted into the frame 2 and the shank portion 3 from the entry 3 a opening on the rear end surface of said shank portion 3, the tip 6 a of the mandrel 6 is a taper shaped gradually decreasing diameter toward a tip side of the frame 2.

[0034] The section modulus of said frame 2 and said shank portion 3 is set in accordance with a twist, a bending and a mechanical strength.

[0035] And a rear of said mandrel 6 is supported by the adjustable screw 7 provided in the rear of said shank portion 3, floating support of said mandrel 4 is sustained by the clearance S1 in radial direction provided between the outer circumference of the mandrel 6 and the inner circumference of frame 2 and the shank portion 3.

[0036] In this case, said adjustable crew 7 is formed as a cylindrical shape with bottom, the male screw 7 b relatively fitted with the female screw 3 b on the inner circumference of said shank part 3 is provided in the outer circumference of a cylindrical part 7 a of the screw main body, the hole for the shaft 7 b to sustain the rear of said mandrel 6 is provided in the axis of the flange 7 c to be a bottom.

[0037] And in the cylindrical part 7 a, the slot 7 f opened toward rear of adjustable screw is formed due to the adjustment of supporting position for said mandrel 6 by a rotation of this adjustable screw 7, and the pin 9 engaged with said slot 7 f is affixed to the insert shaft portion 8 a of the adjustable ring 8 inserted into the entry 3 a of said shank portion 3 as adjustable method to adjust a tool diameter by moving the potion of axial direction for said frame 2 of said mandrel 6. In this case, the insert shaft portion 8 a of said adjustable ring 8 is fixed to the inner surface of said cylindrical portion 7 a with universal function for sliding, insertion and withdrawal, a movement and a rotation for axial direction is restricted by the pressing force of the set screw 10 screwed into rear of outer circumference of the shank portion 3.

[0038] And in said mandrel 6, the thrust bearing 11 a, 11 b are fixed on a tip side and a rear side of said mandrel 6 by pinching the flange 7 c of said adjustable screw 7, a locating snap ling 12 a, 12 b for a bearing to adjust a position of an axial direction of a thrust bearing 11 a,11 b are installed in outside axial direction of the thrust bearing 11 a,11 b, moreover the compressing coil spring 13 is equipped as an elastic method to stimulate an elastic force between a tip side of a locating snap ling and the flange 7 c of said adjustable screw 7.

[0039] Accordingly, the relative position in an axial direction of the adjustable screw 7 and the adjustable ring 8 are changed by a normal and a reversal rotation of said adjustable ring 8. Specifically, tweaking a predetermined tool diameter is feasible by moving the position of a tip of the taper shaped mandrel 6 for the roller 5.

[0040] Of course, when no loading condition, in other words, before processing an inner work hole W1 of a work W, keeping a diameter (following is a tool diameter) of an enveloping circle of said roller 5,5 a maximum state is feasible by the set force of said compressing coil spring 13, and preventing the roller 5,5 in this state from rickety condition is also feasible.

[0041] And an inclined angle (feed angle) θ of said groves 4,4 for engaging roller and a clearance S2 between a rear end surface of the mandrel 6 and a tip end surface of an insert portion 8 a of an adjustable ring 8 are provided so that said mandrel 6 is moved from said frame 2 side to said shank portion 3 side to resist an impetus of said compressing coil spring 13 as an elastic method when said frame 2 is inserted into a work hole W1 of said work W and is driven in a reversal direction by a rotation drive force of a machine tool. Moreover, in said adjustable ring 8 and the insert shaft portion 8 a, the passage 14 as a hole or a slit opening between these two surface is provided to supply a coolant into said shank portion 3.

[0042] Following is the explanation for the action of the roller-burnishing tool 1 regarding to an embodiment of the invention. As illustration of FIG. 2 and FIG. 3, insert said frame 2 into a work hole W1 of work W with imparting a rotary drive in a normal direction. Roller 5,5 are contacting with an inner surface of a work W1 and an outer circumference of tip 6 a of the mandrel 6, and begin to rotate by a friction force mutually generated in between. In this time, since said mandrel 6 is supported by said roller 5,5 and said hole 7 d of said adjustable screw 7, and free from a rotary direction, these cause said mandrel 6 to dependently rotate in accordance with a rotation of said roller 5,5.

[0043] The compressing spring 13 is fitted into the shank portion 3 always pushes the mandrel 6 into an tip side, consequently, an initial adjustment of a tool diameter in non loading condition is sustained. As illustrating in FIG. 3, however, since the treating force is arisen in the mandrel 6 by the action of said feed angle θ when reversing the rotation of the frame 7, a tool diameter is shrunken when the retreating force exceeds the force of compressing spring13.

[0044] In this way, owning to the structure of driving the frame 2, it allows roller 5,5 to perform a rapid feed processing 3˜4 times faster than the conventional structure of driving mandrel. Specifically, by the principle of planetary movement, comparing when imparting a rotary motion to the conventional mandrel 114 by 1000 mim-1 with when imparting a rotary motion to the frame 2 of this invention by 1000 mim-1, even though the feeding speed of this inventive one become 3˜4 times faster, that can gain same completion in the same feeding stroke as conventional one. Of course like previous mentioning, owning to the structure to perform a rotary driving of the fame 2, it leads high rigidity compared with the conventional structure of driving the mandrel 114.

[0045] Owning to the structure of coaxially positioning the mandrel 6 in an axis of the frame 2, it leads improved rotation accuracy and a capable for a rapid rotation. Accordingly the whole efficiency improves 6˜7times as much as the conventional one is.

[0046] And as previous mentioning, under the condition to perform a rotary drive of the roller-burnishing tool 1, even though a rotary speed of the mandrel 6 is increased, the rotation is smooth due to being supported by a pair of thrust bearing 11 a, 11 b.

[0047] As FIG. 2 indicates, said mandrel 6 is not restricted in a radial direction, and also as FIG. 5 indicates, that is supported by floating in the clearance between an inner diameter of the frame 2 and an outer diameter of the mandrel 6. And when processing the inner surface of work hole W1 by performing a rotary driving of the roller burnishing tool 1, as FIG. 5 indicates, the core difference of both the roller burnishing tool 1 and the work hole W1 does not cause a deterioration of the formal accuracy. Therefore, more sophisticated completion of work hole 1 is feasible.

[0048] Moreover, since tweaking a tool diameter does not cause a removal of roller 5, 5 in a radial direction, a processing hook holes is effective. Specifically, In case of processing hook holes on the conventional roller-burnishing tool 111, whenever changing a tool diameter, tweaking a tip point of forward of a driving machine is necessary. But in case of roller burnishing tool 1 regarding to this embodiment of the invention, the stroke of driving machine is a constant and tweaking is unnecessary since the position of roller 5,5 is invariable.

[0049] Moreover, connecting the oil coolant supplied from the center spindle of a driving machine (not illustrate) with said passage 14 allows this oil coolant to gush out from the aperture 15 of a tip frame and each grove 4 for engaging roller without leaking to outside on their way. That is why, best lubricant condition is granteened, since processing the inner hole with cooling and lubrication is feasible, more sophisticated mirror finishing is practicable.

[0050] In accordance with hereinbefore-mentioned in said embodiment of the invention, the present invention displays following excellent effects.

[0051] (1) Since adjustment means and elastic means to adjust a tool diameter can be installed in inside of the frame and the shank portion, the whole range from the shank portion to forward frame is subject to be the effective processing length. Accordingly, Installing in a small driving machines which is restrict to a protruding length of a tool such as small machining center or NC lathe is available.

[0052] (2) Owning to the structure of driving the frame, compared with the conventional system of driving the mandrel, rapid feeding process is feasible. Moreover, the rigidity of the whole tool is improved due to the structure to perform a rotary drive of the frame. In addition, since the shank portion is coaxially connected with the frame, a rotation accuracy is improved, the rapid rotation is feasible and a significant improvement of the whole efficiency is practically possible.

[0053] (3) The mandrel is not restricted in a radial direction, since providing the clearance between an inner surface of the frame and an outer surface of the mandrel in order to allow this mandrel to float, sophisticated completion is possible without deteriorating a formal accuracy even under the condition of the core difference between a tool and a work hole.

[0054] (4) Owning to the structure to adjust a tool by moving a taper shaped mandrel in an axial direction and to prevent a position of roller from moving, these lead easy processing hook holes.

[0055] (5) The structure turns into compact and small which reduces the quantity of part and leads less expense. 

What is claimed is:
 1. A roller burnishing tool, comprising: a cylindrical frame for a rolling compaction processing coaxially connected with a cylindrical shank portion performing a rotary drive by mounting in a driving machine, a plurality of grooves to engage multiple rollers for a rolling compaction processing with universal function for rising and setting and rotation in a radial direction formed in circular direction at regular intervals along this frame, a taper shaped mandrel holding in said shank portion and frame with universal function for rotation to support said multiple rollers on a tip by rotation from inside radial direction with engaging said rollers in said grooves, an elastic method to imputes said mandrel from the shank portion side to the frame side provided in said shank portion, and an adjustable method to adjust a tool diameter by moving a position of an axial direction for said frame of said mandrel.
 2. A roller burnishing tool according to the claim 1 of the present invention wherein: a cylindrical frame for a rolling compaction processing coaxially connected with a cylindrical shank portion performing a rotary drive by mounting in a driving machine, a plurality of grooves to engage multiple rollers for a rolling compaction processing with universal function for rising and setting and rotation in a radial direction formed in circular direction at regular intervals along this frame, a taper shaped mandrel holding in said shank portion and frame with universal function for rotation to support said multiple rollers on a tip by rotation from inside radial direction with engaging said rollers in said grooves, an elastic method to imputes said mandrel from the shank portion side to the frame side provided in said shank portion, an adjustable method to adjust a tool diameter by moving a position of an axial direction for said frame of said mandrel, and furthermore, a feed angle to allow said mandrel to move from said frame side to said shank side when reversing the rotation of said frame to a processing direction provided in both said grooves of said frame and the rotation axis of said rollers.
 3. A roller burnishing tool according to the claim 1 of the present invention wherein the clearance is provided in between an outer circumference of said mandrel and an inner surface of said frame to allow this mandrel to float.
 4. A roller burnishing tool according to the claim 2 of the present invention wherein the clearance is provided in between an outer circumference of said mandrel and an inner surface of said frame to allow this mandrel to float. 